1. Field of the Invention
The present invention generally relates to a modular electrical connector, and more particularly to a stacked modular jack connector for use in the transmission of high frequency signals.
2. Description of Prior Arts
Data communication networks are being developed which enable the flow of information to ever greater numbers of users at ever higher transmission rates. However, data transmitted at high rates in multi-pair data communication cables has an increased susceptibility to crosstalk, which often adversely affects the processing and integrity of the transmitted data. The higher the frequency of signal is, the more serious the crosstalk issue is.
In the case of local area network (LAN) systems employing electrically distinct twisted wire pairs, crosstalk occurs when signal energy inadvertently xe2x80x9ccrossesxe2x80x9d from one signal pair to another. The point at which the signal crosses or couples from one set of wires to another may be within the connector or internal circuitry of the transmitting station, referred to as xe2x80x9cnear-endxe2x80x9d crosstalk.
Near-end crosstalk is especially troublesome when high frequency modular electrical connectors are in use in LAN system. Such modular electrical connectors include modular plugs and modular jacks. Specifically, a two-port modular jack which is employed in a stack LAN connector assembly, generally includes an upper port and a lower port, each port having a plurality of conductors received therein. Conductors from the upper port have to be always arranged or placed outside of conductors from the lower port underneath the upper one, i.e. the upper conductors are usually longer than the lower ones which may rise the problem of electrical resistance and impedance matching in high performance circuit. And the layout of mother board, onto which the modular jack is mounted, is restricted and parts for the lower port should be always finished first during the assembling process. Such configurations of a stacked modular jack assembly are presented in several patents as introduced hereinafter.
U.S. Pat. No. 5,531,612 issued to Goodall et al on Jul. 2, 1996 and its corresponding European Patent Application No. 94308734.6, disclosed a modular jack assembly for mounting to a printed circuit board. The modular jack comprises a plurality of modular jacks assembled to a common integral housing and arranged in two rows. It is easy to see that the contacts of an upper modular jack are longer than that of a lower modular jack in a same column. Similarly, U.S. Pat. No. 5,639,267 issued to Maxconn Incorporated on Jun. 17, 1997 and U.S. Pat. No. 6,267,628 issued to Stewart Connector Systems, Inc. on Jul. 31, 2001, respectively illustrate a modular jack assembly which comprises an upper contact pin longer than a lower contact pin.
Hence, an improved stacked modular jack connector is desired to overcome the disadvantages of the prior art.
Accordingly, an object of the present invention is to provide a stacked modular jack connector for use in data transmission at high frequencies.
Another object of the present invention is to provide a stacked modular jack connector which reduces near-end crosstalk during data transmission.
In order to achieve the above-mentioned objects, a modular jack connector adapted for mounting onto a mother board includes an integral housing, a contact insert received in housing, an upper LED insert and a lower LED insert assembled in the housing and a metal shield. The contact insert comprises an upper insert subassembly, a lower insert subassembly, and a noise suppressing device. Each insert subassembly has a circuit board having conductive traces arranged thereon and a set of contacts electrically connected to the circuit board. The noise suppressing device comprises two magnetic modules and a third circuit board. Each magnetic module electrically connects to a corresponding set of contacts via the conductive traces which performs to affect the cross-talk occurred between the contacts. The magnetic modules each comprise upward pins disposed on a top face, downward pins disposed on a bottom face for electrically connecting to the mother board, and coils conductively interconnecting the upward and downward pins. Some of the upward pins of the two modules all penetrate through rear portions of the two circuit boards, and can be selectively soldered onto one of them to electrically connect to the contacts soldered on the same circuit board. The rest of the upward pins electrically contact to the third circuit board.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description of the present embodiment when taken in conjunction with the accompanying drawings.